Jet air pump



June 27 1939. j J, WALL EJ642615 JET AIR PUMP Filed March 25, 1938 2Sheets-Sheet 1 J. J. WALL JET AIR PUMP June 27, 1939.

Filed March 25, 1958 2 Sheets-Sheet 2 Patented June 27, 1939 UNITEDSTATES PATENT OFFICE 4 Claims.

This invention relates to improvements in pumping apparatus, generallyof the type known asjet pumps. distinguishes from rotary, piston andother kinds of pumps by the employment of nozzles which produce fluidjets in such a manner as to draw in low pressure fluid and expel itunder a degree of compression.

One of the outstanding advantages of a pump of the type hereindisclosed, is the absence of moving parts which, ordinarily are subjectto more or less rapid wear and breaking down, said absence also havingthe result that the pump may be operated continuously for long periodswithout any perceptible wear and with little or no noise. Theeffectiveness with which its simple construction can be made to work isa recommendation for its use in substitution for the known kinds ofmechanical pumps in a wide variety of uses. With this preamble in mind,the

objects of the invention areas follow:

First, to provide a pump of the character described for compressing airby means of steam jets in combination with water jets or sprays,

arranged in such manner and in such numbers as to entrain the desiredquantity of air and compress the same without an excessive rise in tem-.perature, thus accomplishing very nearly isothermal compression.

Second, to effect complete or nearly complete condensation of the motivefluid before it enters the throat of the Venturi tube, thus reducing thevolume of the fluid which must go through said tube.

Third, to thoroughly mix and cool the fluids to reduce their volume,thereby making it possible to use a smaller Venturi tube than hasheretofore been the case.

Fourth, to so interrelate the nozzles through which the respective hotmotive and condensing fluids are introduced, as to minimize the transferof heat before said fluids emerge from said nozzles.

4 Fifth, to effect a thorough mixing of the motive,

cooling (or condensing) and entrained fluids as quickly as possibleafter the motive and cooling fluids have left their nozzles, for thepurpose of transferring the maximum amount of the heat and kineticenergy from the motive fluid to the cooling and entrained fluids.

sixth, to arrange the outlets of the nozzles in such a way that thedischarge side of the nozzles assemblage roughly takes the form. of acone to conform so far as is practicable, to the direc- This type, asits name indicates,

' zle holder. 10

Figure 4 is an inverted perspective View of the steam nozzle holder.

Figure 5 is a perspective view of the water nozzle manifold.

Figure 6 is an inverted perspective view of said. 15 manifold.

Figure 7 is a sectional View of a modified form of water nozzle.

Figure 8 is a sectional view of a modified Venturi tube.

' In carrying out the invention provision is made of a chest I which hasan inlet 2 for the admission of steam or equivalent motive fluid. Thechest I is flanged at 3 for the reception of bolts 4 (Fig. 2) whichsecure the steam chest to the 25 main body 5 by virtue of being screwedinto the corresponding flanges 6 of the latter. The main body 5 has acylindrical recess I which ends at a supporting step 8. Thisstep meets atapering opening 9 which, as shown in Fig. 1, communicates with achamber Ill which is. combined suction and mixing chamber.

A large opening II admits air or other fluid to be entrained, to thechamber Ill. It is here that the air is made to commingle with themotive 35 and cooling fluids in the manner presently explained. There isa. rectangular opening I2 in the main body 5 at a location opposite tothe opening II. A discharge opening I3 is situated in a plane at rightangles to the plane of the 40 opening II. The perimeter of the dischargeopening I3 is flanged at I4 so that the flange I5 1 of a Venturi tube Itmay be secured in place by any suitable means.

Said tube comprises a downwardly converging 45 passage H whichcommunicates with the/throat I 8 of the Venturi tube. From there saidtube has a downwardly flaring passage I9 which is flanged at 20 forattachment to a pipe line or the i like. 59

Reference is made to Fig. 8 at this point. Here the downwardly taperingtube Ito. ends at IBa where the throat I8 would begin. The mouth at lawopens into the cylindrical pipe I a. which is flanged 20a. forattachment to a pipe line as above. 55

From this it will be understood that the Venturi may comprise aconverging tube of different types.

The recess I and tapering opening 9 contain a holder 2| which is crosssectionally shaped to fit the contour 1, 8, 9. This holder and itscarried parts is capable of being removed from its assemblage in thepump by first taking off the steam chest I. A plurality of steam nozzles22 is carried by the holder 2| in a circular series (Figures 2 and 3).Each of these nozzles has a tubular portion 23, a threaded shoulder 24and a non-circular head 25. In each case the threaded shoulder isscrewed into a bore 26 which goes through the bottom of the holder 2|and through a conveniently provided boss 2'! which adds to the length ofthe thread passage and improves the holding quality of the threads whenthe noz zle is driven home by applying a wrench to the head 25, Thepassageway 28 within each nozzle 22 is of the Venturi form shown.

It is to be observed that the axes 29 of the various nozzles 22 are setat a pitch. These axes, if extended as indicated by the extension lines30, converge to a common center in the vicinity of the Venturi throat$8. The configuration thus depicted is generally in the form of a cone.A similar principle obtains in the positioning of the circular series ofwater nozzles 3|, These nozzles are screwed into threaded bores 32 inthe nether side of a manifold 33 which is fitted into place within thechamber l0 through the previously mentioned opening l2. Said manifold isflanged at 34 and it is through these flanges that suitable securingmeans are driven into the main body 5.

The manifold 33 has a hollow interior 35 into which water undercomparatively low pressure enters through a feed pipe 36. It is with thehollow interior that the nozzles 3| communicate. It will be seen in Fig.1 that the axial lines 31 of the water nozzles converge in common withthe axes of the steam nozzles, all of the axial lines falling within thepreviously mentioned cone configuration.

Said configuration is augmented by the stepped arrangement of thevarious nozzles. It will be seen in Fig. 1 that there is an, outermostseries of water nozzles, the orifices of which are in a plane slightlyhigher than the orifices of the steam nozzles in the next series readingin toward the center of the pump. Then there is a second series of waternozzles, and the crown of the whole series comprises the central nozzle38, the orifice of which tops all of the others. The central nozzles 38is also for the ejection of steam inasmuch as it communicates with theinterior of the chest I. Although its internal configuration is slightlydifferent from the internal configuration of the other steam nozzles,yet its formation is that of a Venturi as is also its function.

Again considering the manifold 33, it will be seen that there are fairlylarge openings 39, 40, for the steam nozzles. The openings 39 occur in acircular series while the opening 40 is only a single one. These variousopenings are sufficiently oversized to prevent any of the steam nozzlesfrom touching the manifold 33. This arrangement minimizes the transferof heat from the hot steam to the relatively cold water.

Instead of leaving the bores of the water nozzles-3l perfectly plain, asshown in Fig. 1, they may be modified according to the plan in Fig. '7.Here the nozzle 3lahas. a bore 4| which communicates with a counter-bore42. The latter provides a shoulder 43 on which the end lugs 44 of aspiral insert 45 are rested. The spiral insert tends to impart a whirlto the water, and in doing so reduces it to a mist which facilitates thepreviously mentioned comrningling function.

The operation is readily understood. Jets of steam moving at a highvelocity, issue from the nozzles 22, 38. in the directions of the axiallines previously mentioned and indicated in Fig. 1. These jets movedownward into the Venturi tube l6. At the same time jets of water issueat a lower velocity from the nozzles 3|. These are also directeddownward into the Venturi tube 16.

Inasmuch as the opening ll communicates directly with the outside air orwith some other space to be exhausted, such air will be drawn in becauseof the vacuum which the steam and water jets tend to produce in thechamber I0. The air stream generally designated by the arrows a, makes aright angle turn and flows into the passage I! in common with the motive(steam) and cooling (water) fluids. A large amount of the incoming airis entrained by the steam and water jets and thus there enters theconverging tube I I a mixture of steam, water and air.

As this mixture moves downward, most of the steam comes into contactwith the colder water and air and is condensed. At the same time most ofthe velocity and kinetic energy of the steam are imparted to the air andwater. Because of the fact that the three fluids are thoroughlycommingled it follows that the steam is condensed, reducing the volumeof the mixture whereb the velocity of the air and water are greatlyaccelerated.

It is important to note that most or all of the steam is condensed inthe region roughly encircled at 46, which lies just outside of theVenturi tube l6. In other words, most or all of the steam condensationoccurs before it can enter or go through the Venturi tube. This functionreduces the volume of the mixture which has to be forced through thetube, and makes possible a. great reduction in the throat area of theventuri, makes possible a higher operating efliciency, and makesunnecessary the use of an after condenser.

As the mixture flows through the tube, reaching the flaring passage [9,its velocity decreases and pressure increases. Ordinarily when air iscompressed, its temperature rises but according to this invention theparticles of water which are mixed with the air absorb the heat ofcompression and prevent any rapid rise in temperature. Thusapproximately isothermal compression is achieved and there emerges fromthe flaring tube I9 a mixture of cool, compressed air and finely dividedparticles of water. The excess moisture may then be removed from the airby a suitable separator (not shown). Two or more ofthese pumps orcompressors may be connected up in series or stages to attain higherpressures or vacuum that is possible with the single stage illustrated.

This pump is not confined to the use of steam, water and air as therespective motive, cooling and entrained fluids, because the pump isadaptable to other applications wherein other types and combinations offluids can be utilized. For example, in refrigeration and airconditioning, the compressor will operate with ammonia gas as the motivefluid, liquid ammonia as the cooling fluid and ammonia gas as theentrained fluid.

Instead of drawing atmospheric. air in at the opening I I the pump maybe used for evacuating vapors of various kinds from vacuum stills, tiremolds, deodorizers, etc. In many of these applications fluids other thansteam, water and air will be employed.

The arrangement of nozzles, both steam and water, is mainly suggestive.The numbers of nozzles in the various series can and will be increasedor diminished according to the size of pump to be developed. Still theactual number of nozzles of each kind for a particular installation issubject to being worked out according to a mathematical formula. If toomany nozzles are used the ensuing large number of small jets willentrain too much air and the compressor will not be able to raise thepressure very high. On the other hand if too few large nozzles are useda small amount of air will be entrained, poor mixing will result, and. alarge amount of steam would go through the Venturi tube in anuncondensed state and still moving at a high velocity, for which reasonthe operating effiiciency would be low.

It is not always necessary to arrange the various nozzles in concentriccircles as shown. The essential thing is to space the nozzles evenly.The principle of next importance is to alternate the motive and coolingfluid nozzles (Fig. 1) so that no two motive fluid, nor any two coolingfluid nozzles are adjacent. This arrangement produces the bestinterspersement of the motive and cooling fluid jets.

Although the illustrations and description are based on an erectposition of the pump, it is not to be thought that the pump will workonly in this position. It is true that it will work best in thisposition but it will do so almost equally as well mounted horizontallyor in any desired intermediate position. By way of a further permissiblevariation it is not imperative that the sets of nozzles 22, 3|, shallalways be set so that their axes converge to a common center in thevicinity of the Venturi throat. They can be set approximately paralleland still have a fairly good operation, although the convergingnozzle-axis arrangement is the best and is preferred.

While referring to the disposition of the nozzles, it is desired topoint out that the circular arrangement (Figs. 3 and 6) does not have tobe adhered to in all cases. The nozzles could be mounted in rows to forma square, triangle or the like, and to suit this modification theVenturi tube can be cross-sectionally shaped to match.

I claim:

1, A pump comprising a Venturi tube having a suction opening and athroat, a hot motive fluid chest, a set of nozzles pendent from thechest communicating therewith and being directed past the opening towardthe throat, a cooling fluid chamber having oversize openings throughwhich said nozzles project providing ample spaces around the nozzles toprevent the transfer of heat, and other nozzles carried by said chamber,communicating with the interior and being directed to the throat, thevarious nozzles being interspersed to produce a commingling of themotive and cooling fluids prior to their entry into the tube.

2. A pump comprising a body having a suction opening, a Venturi tubeextending from the body and communicating therewith, a member fittedupon the body defining a chest, a nozzle holder seated on the bodybeneath the chest, a plurality of nozzles pendent from said holder, amanifold carried by the body and having openings through which nozzlesextend without touching the sides of the openings, and other nozlespendent from the manifold, the various nozles being interspersed witheach other and set at such pitches that their combined axes define acone.

3. A pump comprising a mixing chamber having a suction opening, aVenturi tube pendent from the mixing chamber, a hot motive fluid chestsuperimposed upon the mixing chamber and providing a cover thereforcontiguous to the suction opening, a set of nozzles pendent from thechest communicating therewith and being directed toward the Venturitube, a cooling fluid chamber supported by the mixing chamberindependently of said chest, said chamber having openings through whichsaid nozzles extend, and other nozzles carried by the cooling fluidchamber communicating with the interior thereof and being distributedbetween the nozzles of the chest.

4. A pump comprising a mixing chamber having confronting openings, oneof which comprises a suction opening, a Venturi tube pendent from themixing chamber, a manifold inserted in the other one of said openings,providing a closure for said other opening and having a plurality oftransverse openings, nozzles attached to the manifold and communicatingwith the interior thereof, said nozzles being interspersed with saidtransverse openings, a hot motive fluid chest seated in the mixingchamber in spaced relationship to the manifold, and nozzles carried bysaid chest projecting through the transverse openings but in spacedrelationship thereto.

JOHN J. WALL.

